Heat cleaning oven with shuttered oven door window



' June 3, 1969 Filed Feb. 27, 1967 E- H. FILIPAK HEAT CLEANING OVEN WITH SHUTTERED O'VEN DOOR WINDOW Sheet LATCH, LOCK TIME AND SAFETY SWITCHES OVEN TEMPERATURE CONTROL so I SELECTOR SWITCH Jfine 3, 1969 HEAT CLEANING OVEN WITH SHUTTERED OVEN DOOR WINDOW Filed Feb. 27, 1967 Sheet NdE I l I I I I .IIl Illlil'll v 4| v V I I i I flair! United States Paten F 3,448,244 HEAT CLEANING OVEN WITH SHUTTERED OVEN DOOR WINDOW Edmund H. Filipak, Lexington, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 27, 1967, Ser. No. 618,806 Int. Cl. F21d 11/00 U.S. Cl. 219-412 4 Claims ABSTRACT OF THE DISCLOSURE Heat-cleaning oven structure provided with a door having a viewing window therein, the door being provided with movable shutters on its inner face adapted to be positioned to shield the viewing window from the intense heat of the oven during a heat-cleaning operation, and with interlock means being provided to prevent operation of the oven in a heat-cleaning cycle except when the shutters are in a position shielding the window.

CROSS REFERENCE TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION The field to which this invention pertains is that of domestic cooking ovens of the heat-cleaning type and, in particular, to such oven structures including an oven door provided with a viewing window.

While oven doors with viewing windows are well known in the oven art generally for use during cooking operations, oven doors with viewing windows have not been applied to the commercial models of heat-cleaning ovens to my knowledge. Ostensibly, such viewing windows have not been used because the high temperature in the oven during the heat-cleaning cycle might damage the window, or perhaps raise the temperature of the accessible portion of the window to a degree dangerous to those who might touch it. Of course, there is also the possibility of the high temperature ultimately weakening the window so that if broken during a heat-cleaning cycle, the excessive air entering the oven would create a dangerous combustion condition. Finally, any visible ignition or flames occurring occasionally within the oven during heat-cleaning could unduly alarmthe user.

SUMMARY OF THE INVENTION This invention aims to provide an oven structure including a viewing window in the door which is adapted to be shielded by shutter means during a heat-cleaning cycle to eliminate or avoid the noted objections. In accordance with the invention, it is also contemplated that the shutter structure be arranged so that a heat-cleaning operation may not be carried out unless the shutters are in a position to shield the viewing window during the heat-cleaning cycle. This is accomplished in accordance with the invention by the provision of means responsive to the position of the shutter means in a shielding position to permit energization of the oven heating elements for a heat-cleaning cycle.

3,448,244 Patented June 3, 1969 "ice DRAWING DESCRIPTION FIGURE 1 is a fragmentary, partly-broken isometric view of the front of a domestic oven of the heat-cleaning type provided with one embodiment of shutter means according to the invention shown in a position to shield the viewing window of the door;

FIG. 2 is a fragmentary, partly-broken view of the interior face of the oven door with the shutter means shown in a closed position in solid lines, and with the right half of the shutter means shown in an open position in phantom line outline;

FIG. 3 is a vertical section corresponding to one taken along the line III-III of FIG. 2; and

FIG. 4 is a simplified circuit diagram showing the relationship of the shutter interlock switch in one electrical circuit which may be used for accomplishing a heatcleaning operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the cooking range illustrated in FIG. 1, the oven cavity 10 is peripherally framed at its open front face by opposite vertical side members 12, horizontal top member 14, and horizontal bottom member 16. A bottom heating element 18 normally used for baking is located at the floor of the cavity, and a top heating element (not shown in FIG. 1) closely underlies the top wall of the cavity. The top element is used for various cooking operations such as broiling, and may also provide the heat during the heat-cleaning cycle in accordance with the disclosures of the previously-noted patent applications.

The open front face of the oven cavity is closed during the heat-cleaning cycle by the oven door 20 which is hinged to pivot about a horizontal axis adjacent the bottom framing member 16 of the cavity. The inner face panel of the door has angle-shaped members 22 and 24 secured in opposing, parallel relation to each other to provide upper and lower tracks for the respectively opposite edges of the pair of shutters 26 and 28. The shutters are shown in their closed position in FIG. 1 covering a viewing window 30 located in the central portion of the door 20.

Details as to the specific construction of parts of door 20 and shutters 26 and 28 are omitted herein since the generally well recognized principles relating to insulated oven door construction may be applied. Briefly, these principles include the provision of heat breaks in the way of heat-resistant gaskets between inner panels directly exposed to high temperatures, and the connected outer panels, to limit the rate of heat conduction. The same principles applicable to door construction apply to the shutters, which preferably are hollow structures filled with thermal insulation, with the junctions between the inner and outer panels including a heat break material.

The parts of the structure which operate to insure that a heat-cleaning cycle may not take place unless the shutters are in a closed position shielding the viewing window include an interlock lever 32 (shown in FIG. 1 projecting out of the slot 34 in the top angle 22), and a shutter interlock switch 36 mounted in the range platform above the oven. The switch is a normally open switch having its actuating lever 38 projecting downwardly into a forwardly-open recess 40 in the top horizontal member 14 of the oven front frame. When the oven door 20 is shut with the shutters closed, the interlock lever 32 engages the actuating lever 38 to close the switch. This places the oven control circuit in a condition permitting a heat-cleaning cycle if all other parts of the control are also in a condition to permit the cycle.

The manner in which the interlock lever 32 operates in accordance with the positioning of the shutter means is best illustrated in connection with FIGS. 2 and 3. The

interlock lever, in the exemplary embodiment, is of right angle shape in transverse cross-section and includes an upper longer leg 42 and a lower shorter leg 44 forming an obtuse angle. Their junction is pivotally secured to a corner of the right shutter 26 by a pin 46. When the shutters are out of abutting edge engagement, the interlock lever may be pivoted, or drops by gravity to its broken line position of FIG. 2. When the shutter 26 is moved to its closed position covering one-half the viewing window, and the opposite shutter 28 is then moved into its window covering position, the edge of the shutter 28 engages the lower leg 44 and pivots the interlock lever so that upper leg 42 projects up through the slot 34 in the top track 22. It will be appreciated that if shutter 26 is in its shielding position but shutter 28 is not, the interlock lever 32 will remain in its recessed position and a heat-cleaning cycle may not be initiated. Also, the slot 34 is located to permit raising the lever only if the shutters are in their proper positions centered over the viewing window. For ease in moving the shutters to their proper positions for both shielding and when out of obstructing position relative to the viewing window, suitable stops (not shown) may be provided in the shutter tracks.

The relationship of the shutter interlock switch 36 in one type of circuit which may be used for controlling the oven in a heat-cleaning cycle is illustrated in FIG. 4 in which block representations indicate the main parts of the circuit. For heating of the oven cavity in accordance with the previously noted patent applications, the broiling element 48 is energized across lines L1 and L2 when the selector switch 50 is in a clean position, and the relay switch 52 controlled by the oven control relay circuit 54 is closed. The shutter interlock switch 36 is in the circuit which includes various switches concerned with insuring latching and locking of the door, as well as time responsive and safety switches, all indicated by the block 56 and in series with the primary of a transformer 58 for energizing the oven temperature control. Reference may be had to the previously noted patent applications for details as to the parts of the circuit indicated by the block representations. Essentially however, the normally open shutter interlock switch 36 must be closed, indicating the shutters are in a closed position and the oven door is shut, for the transformer primary circuit and oven temperature control to be energized so that a heat-cleaning cycle can proceed.

While only one specific embodiment for carrying out the invention has been described, it will be understood that other arrangements within the scope of the concept may be devised. For example, the shutters may be hinged rather than slidingly supported with rotation of the shutters to a closed position placing an interlock lever into an actuating position. In an alternate arrangement, suggested by another, the movement of the shutter to a shielding position may be related mechanically to the ability of the door latch to be moved to a latching position.

I claim as my invention:

1. In a heat-cleaning oven:

means defining an oven cavity including heating element means adapted to be energized for carrying out a heat-cleaning operation in said oven cavity;

a door mounted on said oven for closing said oven cavity for a heat-cleaning operation, said door including a centrally located viewing window therein;

thermally insulated shutter means on-the inside face of said door in a position accessible for manipulation by simply opening said door and without further manipulation of said door required, means mounting said shutter means for operation between one position shielding said viewing window from, and interposed physically between, the interior of the oven cavity and another position exposing said viewing window;

electrical control means including a circuit for controlling energization of said heating element means for a heat-cleaning operation, said circuit including a normally-open electrical switch mounted on said oven, said switch having a closed position required for energizing said circuit to obtain said heat cleaning operation; and, switch-engaging means carried by said shutter means for closing said switch, means on said mounting means to register with said switch engaging means when said shutter means is closed and said door is shut.

2. In an oven according to claim 1:

said shutter means comprises a pair of sliding panels located at opposite sides of said window and movable into generally abutting edge relationship overlying the viewing window of said door; and

said switch-engaging means is operable to engage said switch only when both of said shutters are in generally abutting relationship and are generally centered relative to said viewing window.

3. In an oven according to claim 2:

track means mounted on said door and slidably carrying said panels; and

one of said panels carries said switch engaging means in the form of a lever operable to project out of said track means when said panels are in edge abutting relationship, and are centrally located over said viewing window.

4. In an oven according to claim 3:

said track means includes means defining a slot therein located to register with said lever when said one shutter is properly located for shielding said window, said track means precluding projection of said lever means in other positions of said one shutter.

References Cited UNITED STATES PATENTS 1,999,782 4/1935 Rehm 126-200 2,908,254 10/1959 Marigold et al. l26-20O 2,926,658 3/1960 Ligon 126-200 3,191,240 6/1965 Slaman et al l26200 X 3,311,106 3/1967 Baughman et a1 126-200 3,362,396 1/1968 Hurko 126-200 BERNARD A. GILHEANY, Primary Examiner.

H. B. GILSON, Assistant Examiner. 

